Contribution of tertiary amino groups to Re(VII) biosorption on modified corn stalk: Competitiveness and regularity

► A low corn stalk gel modified by di-n-octylamine was developed. ► The novel gel exhibited a high affinity for Re(VII). ► Re(VII) adsorption capacity and selectivity depend on basic strength and steric hindrance of the modified gels. ► The recovery of Re(VII) in the presence of excess of other metal ions was possible.